This application claims priority based upon German patent document 199 43 589.8, the content of which are incorporated herein by reference.
1. Field of the Invention
The invention relates to light guides, and in particular, mushroom-shaped light guides.
2. Related Art
A mushroom-shaped light guide is used e.g. in a preset potentiometer of DE 197 12 294, whereby the light guide is connected to a control knob and has a light incidence surface in the rotational center. In front of the latter, a light source is arranged. The light guide""s body ends with its circumferential part in a transparent case that has a scale, which can be seen externally.
However, it has been found that the invention of the related art provides insufficient illumination.
Therefore, an object of the present invention is to provide a mushroom-shaped light guide with improved illumination.
This object and other objects of the present invention are achieved by providing a Mushroom-shaped light guide for a homogeneous illumination of a circular scale of a motor vehicle operating device by means of a light source (LED) arranged opposite a light input surface of a mushroom-shaped cone, wherein a light input surface has a cylindrical recess, and edge of which is rounded off in a circle with a radius R between a lateral surface and an axial surface, and a base of which is provided in a form of a ball surface which projects centrally, whereby the mushroom-shaped cone has a conical end section.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.